There are several animals that are kept in aquaria, that are not fish. Some of the common non-fish aquarium species are included here.
There are several invertebrates kept in aquaria, snails being the most common. When keeping invertebrates remember that the pH should be kept above 7.0, and the water should be copper free. Always aerate the water well.
Apple snails (Ampullaria, Pomacea): Apple snails can reach the size of an apple and come in a variety of colors. These snails breathe at the water surface through a proboscis, and may move above the water and right out of the tank if there is not a tight-fitting cover. This snail eating decaying matter and flake foods. If the Apple snail is not fed sufficiently, it will eat plants. The eggs are laid above the water.
Ramshorn snails (Helisoma): There are a wide variety of ramshorn snails which have a shell shaped like a ram's horn. Ramshorn snails reach a size of 0.8" (2 cm). Ramshorn snails may eat plants and multiply rapidly with overfeeding. Ramshorn snails will eat algae.
Malaysian or Trumpet snails (Melanoides): These snails, having a spiraled shell, bear live young. They move through the substrate loosening it up and consuming debris. These snails do not harm plants.
Mystery snails (Viviparus): These snails reach a size of 0.8" (2 cm) and feeds on algae, plant matter, and excess food. The young are born live. Do not allow the water temperature to exceed 75°F (24°C).
Blue Marron (Cherax tenuimanus): The Blue Marron inhabits pools in West Australia. Use water with a pH from 7.2-8.5, 8-20 dH, 59-72°F (15-22°C). Blue Marron are territorial and each fish require a retreat. This species can be combined with large non-aggressive fish, especially if the movable portion of the claw is removed. Blue Marron feed on decaying matter in nature, and almost anything in aquaria. Before molting, the crayfish may lose color, stop eating, and rest upside down. For two days after spawning, the Marron is vulnerable. The Blue Marron has been bred with some success. Males have projections at the base of the fifth pair of legs, while females have openings at the base of the third pair of legs. The Blue Marron can be induced to spawn by raising the temperature and increasing the period of illumination. The young, numbering as many as 300, can be removed from the underside of the female's tail. The parents are cannibalistic.
Penguin Shrimp (Atyopsis): The shrimp in this genus range in size, though those that do not exceed 4" (10 cm) are recommended for aquaria. This shrimp can be combined with peaceful fish of the upper swimming levels. The Penguin Shrimp feeds on most foods. In a tank with several specimen, young will likely produced as long as there is plenty of cover and algae. The young drop of the underside of the female and try to escape without being eaten.
Red-clawed Crab: The Red-Clawed crab is a species that must be allowed access to the surface. Thus this species is better suited to a brackish water, half-filled aquarium. The Red-clawed crab feeds on any dry food or plant matter. Use a tight-fitting cover. The Red-clawed crab reaches 2.7" (7 cm) and can be combined with other brackish water species. This crab can be kept in hard, alkaline freshwater.
Fiddler Crab (Uca): The Fiddler crab reaches 2.4" (6 cm). This species must have access to dry land, and is best kept in a tank filled only half way with water. Brackish water is preferred, and a sandy beach is suggested. This crab constructs burrows in the sand. The tank should be furnished with a tight-fitting cover. Combine the Fiddler crab with medium sized brackish water species. This species will eat almost any foods.
Amano Shrimp (Caridina japonica): Information coming soon.
African Water Frog (Hymenochirus): These aquatic frogs, up to 3.2" (8 cm), can be kept in a well-planted aquarium housed with peaceful fish species. African frogs eat live foods that reach the substrate, but will not compete for food. This frog is most active at dusk and should be fed after the lights are off so that it is more likely to be able to reach the food.
African Clawed Frog (Xenopus): This aquatic frog, can be kept in an aquarium with medium-sized, peaceful fish. Females reach 5" (13 cm), while males reach 3.2" (8 cm). Feed this frog live food. Breeding produces as many as 15,000 eggs, which hatch after two days. Use water with a pH from 6.5-8, 2-10 dH, 77-84°F (24-29°C).